Football is the ultimate team sport, and while the quarterback is the most important player, he still has only limited control of what his team does each game.

We wanted a way to isolate a quarterback's value when he threw or ran the ball relative to what the rest of his team did on every other play. The method for this was to collect data on expected points added (EPA) from ESPN Stats & Information research. Every play has an expected point total based on factors such as down, distance to go, field position, home-field advantage and time remaining. The higher the EPA, the more successful that play was at helping the team score the game's next points.

Basically, if a quarterback had a great season despite not getting much help from his team's running game or defense, then he'll have a much higher EPA relative to the team's EPA, showing his value, and suggesting that he needs more help around him. Even if the quarterback had an average individual season, a terrible team EPA will prove that he's likely far less of the problem than the rest of the team's flaws.

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When we turn our attention toward the least valuable quarterbacks of 2016, we are mostly looking at quarterbacks who held their teams back in the passing game while the other team elements (running game, defense, special teams) were usually strong.

Some of these quarterbacks still made the playoffs, and some have even been to the Super Bowl before. However, 2016 was not their finest moment. Four quarterbacks even produced less EPA than their teams did, which is difficult to do when so many of the game's biggest plays that lead to points come in the passing game.

We should also note that measuring EPA on passing plays does not separate the quarterback from his receivers or pass blockers. So this measurement filters out the quarterback from the running game, defense and special teams, but not from the rest of his team's pass offense.

Read through our various categories of passers, or skip ahead to the metric of your choice here:

This is a bad look for a two-time highest-paid player in NFL history. Baltimore missed the playoffs for the third time in four years after Flacco squandered the second-highest team EPA of 2016. While the Ravens did not have much of a ground attack (26th in EPA), they did support Flacco with the No. 8 defense in EPA (plus-9.5) and the best special teams (plus-58.6) by a wide margin. In fact, where would the Ravens be without kicker Justin Tucker? He made 38 field goals (out of 39 attempts) while the offense contributed only 30 touchdowns.

Joe Flacco has been at the helm of a handful of playoff victories in his career, but his performance held the Ravens back in 2016. Shelley Lipton/Icon Sportswire